The company is based around a business model where the author pays for the publishing.
The learned authors may pay too much heed to laboratory rats.
The journal allows self-archiving and authors can pay extra for open access.
With vanity publishing, authors pay to have their books published.
At Xlibris, authors pay $200 to $1,600 to publish a book.
Moreover, many professional web designers and authors pay little attention to issues of validity.
To fund the journal, the publication's business model requires in most cases that authors pay publication costs.
That's a big part of what the author is paying you for.
Alternatively, an author who had sufficient money would sometimes keep the copyright himself, and simply pay the printer for the production of the book.